Question

A study is conducted to estimate the average difference in bus ridership for a large city during the morning and afternoon rush hours. The transit authority's researcher randomly selects nine buses because of the variety of routes they represent. On a given day the number of riders on each bus is counted at 7:45 A.M. and at 4:45 P.M., with the following results.

Bus	Morning	Afternoon
1	47	41
2	51	48
3	37	44
4	24	32
5	48	46
6	44	39
7	50	47
8	55	49
9	49	49

Use the data to compute a 90% confidence interval to estimate the population average difference. Assume ridership is normally distributed.

≤ D ≤

Answer 1